1.有线电视数字机顶盒的基本原理有线电视数字机顶盒的基本功能是接收数字电视广播节目。调谐模块接收射频信号并下行变频为中频信号,然后进行A/D转换为数字信号,再送入QAM解调模块进行QAM解调,输出MPEG传输流的串行或并行数据。解复用模块接收MPEG传输流,从中抽出一个节目的PE 1. Cable TV Digital Set-Top Boxes The Basics Cable TV digital set-top box’s basic function is to receive digital television broadcasts. The tuner module receives the RF signal and down-converts it to an IF signal, then performs A / D conversion into a digital signal, and then sends the signal to a QAM demodulation module for QAM demodulation to output serial or parallel data of the MPEG transport stream. The demultiplexing module receives the MPEG transport stream and extracts a program’s PE from it